Finally pulled the codes. I have gotten codes 2-2-1 and 3-1-1. It failed NJ emissions inspection for high NOx. The model doesn't have EGR. Replaced complete exhaust and O2 sensor. Suggestions?

If you have a turbo, check the vacuum diaphragm on the front of the compressor housing (3 10mm bolts hold it on).... I had same results; the diaphragm had dry cracks and a pin hole in it. I could not find replacement for reasonable price so I put a thin layer of high temp engine silicone on the diaphragm and it passed!

Do you have Regina or Bosch FI? O2 sensors are different. Titania for Regina and zirconia for Bosch. I have a '93 940 NA Regina and mistakenly put in a universal Bosch zirconia.

How do you know what you have? I think mine is Bosch but am not certain.

Link to 740 pic with Regina-Rex is below...940 is similar. No AMM and square coil on driver's side strut tower if you have Regina.

http://www.brickboard.com/RWD/?id=599360

try to read the FAQ click on (engine tune and performance)then(emission failed).lot of info there.good luck.charles.

How long was the CAT in their before you got tested? Aftermarket CAT's are Not very good. Also I was told, but I don't believe it, that a cloged flame trap can cause high NOX...

It was a long story. I was almost a year behind in inspections. Didn't know until getting a ticket. Getting consistent high NOx. Replaced complete exhaust w/ after market cat and new O2 sensor. Didn't help much. I posted the problem a few months ago.

Have been travelling a lot. No time to take care of it until now. It has been sitting on our driveway. Two weeks ago our daughter drove it to Newark Airport to pick us up. She got another ticket for the expired sticker (failing to make repair). Ouch!

Removed the flame trap yesterday. It was not clogged. But I will clean it. I loosened the intake manifold, just to make sure it doesn't have EGR because I couldn't find it.

Not only the flame trap but the breather box is what I meant.

Do you mean the plastic tube that holds the perforated cup?

The breather box is below the cup, you follow the cup down to a black box. The one reader mentioned the throttle body to be cleaned, that is what I'm planning on doing next.

No he means the plastic part that is attached to the block. If you c ould post your results I may be able to help. There are several other causes. Is this the Rex sytem or the Bosch system and when was the last time the throttle body was cleaned and is the door to the air cleaner open to admit fresh air? These are just some of the question that need to be addressed. Pauli

Is there anything I should know removing the black box mounted on the engine block? Thanks.

I will try to remove the breather box to clean it. The throttle body was cleaned last night with paint thinner. What door to the air cleaner?

I believe mine is a Bosch. Thanks for your help.

hi there i dont have numbers for you but i put in the A grind cam and a redrilled cam gear set at four degrees advanced. in my experience it gave me the most improvement at high rpms, on my 87 wagon. goes strongest when you need to pass someone. im sure someone will have numbers for you.